nlsList.selfStart {nlme} | R Documentation

## nlsList Fit from a selfStart Function

### Description

The response variable and primary covariate in `formula(data)` are used together with `model` to construct the nonlinear model formula. This is used in the `nls` calls and, because a selfStarting model function can calculate initial estimates for its parameters from the data, no starting estimates need to be provided.

### Usage

    ## S3 method for class 'selfStart':
    nlsList(model, data, start, control, level, subset, na.action, pool)

### Arguments

`model` | a `selfStart` model function, which calculates initial estimates for the model parameters from `data`.
`data` | a data frame in which to interpret the variables in `model`. Because no grouping factor can be specified in `model`, `data` must inherit from class `groupedData`.
`start` | an optional named list with initial values for the parameters to be estimated in `model`. It is passed as the `start` argument to each `nls` call and is required when the nonlinear function in `model` does not inherit from class `selfStart`.
`control` | a list of control values passed as the `control` argument to `nls`. Defaults to an empty list.
`level` | an optional integer specifying the level of grouping to be used when multiple nested levels of grouping are present.
`subset` | an optional expression indicating the subset of the rows of `data` that should be used in the fit. This can be a logical vector, or a numeric vector indicating which observation numbers are to be included, or a character vector of the row names to be included. All observations are included by default.
`na.action` | a function that indicates what should happen when the data contain `NA`s. The default action (`na.fail`) causes `nlsList` to print an error message and terminate if there are any incomplete observations.
`pool` | an optional logical value that is preserved as an attribute of the returned value. This will be used as the default for `pool` in calculations of standard deviations or standard errors for summaries.

### Value

a list of `nls` objects with as many components as the number of groups defined by the grouping factor. A `NULL` value is assigned to the components corresponding to clusters for which the `nls` algorithm failed to converge. Generic functions such as `coef`, `fixed.effects`, `lme`, `pairs`, `plot`, `predict`, `random.effects`, `summary`, and `update` have methods that can be applied to an `nlsList` object.

### See Also

`selfStart`, `groupedData`, `nls`, `nlme.nlsList`, `nlsList.formula`

### Examples

    data(CO2)
    fm1 <- nlsList(SSasympOff, CO2)
    summary(fm1)

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